Continuous imbricated panel type filter



l Feb. 19, 1952 v. DAHLMAN CONTINUOUS INBRICATED PANEL TYPE FILTER FiledFeb. 23, 1949 Zmvenfor VfR/VER DA HL MAN Gttorneg Patented Feb. 19,`1952 CONTINUOUS 'IMBRICATED PANEL 'TYPE' FILTER.

Verner'DahlmanQNew Lennox, Ill., assignor to American Air FilterCompany, Inc., Louisville, 'Ky.,;a corporation of Delaware `@AIpplicatonFebr-.nary 23,.1949,?SerialNo. 77,707

(olgz'isssz) 'Claims.

The-:present invention relates; to an air' lfilter 'oftheoverlapping.panel..type, in which a series,y of overlapped..`lterlpanels. coated with liquidv are carried along.. onfan endlessconveyor toform' a vertical .lterbed or l .curtain extending acrossthe`pa`th of AairV flow. 'One such type ofair lter -ls.dsclosed inPatent 2,167,283, issued `July 25, 1939, to Arthur Nutting.

As ordinarily operated, the. panels on one flight rof thelter areproperly presented in irnbricatedv relation. to Vthe air stream, but onthe .other flight vthey are turned and are so. imbricated that theypressurerof v.the air .stream can separate the -panels and passtherebetween.. unless additional Furmeans is provided. toA restrain the4panels. thermore, the turning ofthe panels causes them topresentdownstream the. face which was for- :merly presented-upstream,with consequent vdisadvantage thatdustaccumulated on that filter facemay beblownof intothe air stream.`

.It is an object of the presentinvention to proavide: an overlappingendless, panel type, lter in .which the panels are rearranged atthe..return flight. in inversed overlapping relation to successively.restrain thewYpanels-against separation by theforce ofthe air stream.passing. therethrough.

-A further object Vis the. provision. of an overlapping panel doublecurtaintype filter in which -the Ipanels present .the same. face.upstream in .reach ight. or curtain.

A further object is the provisionof an endless ...type-panel -lterhaving atransfer and rearranging mechanismior transposing thepanelssuccessively fromone ight to `the nextflight in .nversedimbricatedrelation.

, InV accordance withthe present Ainvention, there isprovided conveyor'means forremovably carrying imbricated panels of. a lter medium across.the air stream to befiltered, and a transfer means .../sarranged atythe end of the course to remove `and separate the panels-andsuccessively replace .thepanels in inverse overlapped relation. forthe-returntravel across the air stream. This provides a double curtain ofimbricated panels yin Whichthe panels, present the same face upstream isaccomplished'by the provision of 1 a ytransfer.

ingsin which is..illustra.tedv ai preferred embodiment. of theinvention-byway of example/and wherein:

'mechanismV meeting or intersecting' an `endless conveyor and whichserves to. bodily remove each .lter panel from the conveyor whenthai-,'"lter panel reaches the end4 of acourse,'bodly`trans fer thepanel to thebeginning of thereturn course, and there. reassemblethe"lter`panel"in inversed overlapping relationtfto the preceding,panel.. on the conveyory for' .thev return course.'

The-invention Willi bef described in greaterdetail in connectionWithithe accompanying ldraw- Figure 1 lis a front ell'avation-oi`thelinvention, .Figure 2. is a. vertical sectional" View taken on line2`-2. of .Figure 1,v

Figure" 3l i`s.-.` an enlarged View ofa detalfand Figure 4l is asectiontaken on line '4 5-4 f Figure -3. Y Referring to the drawing,jtherei'sshow'n a cabinet. or casing -l having' ai front: inlet opening 2A a.rear outlet. openingV k3.; and' a' trough` 4 at the bottom for Washing'ud.AV At the'bottom ,agshaft V'.SY ist. suitably journalled at each'lside'l',l 6 vo f the housinggand carries at each end chain sprockets 11.and. transfer sprockets fwhicli sprockets `rotate together. At the. topof thecasingare supported stub shafts-'9 at eachjsidav and 'each shaftcarries a` chain sprocl'retVv I'l ,and'a transfer'V sprocket I"2.

.An endlesslconveyor chain |3 extends around each pair of.chainfspro'ckets' comprisingA a sprocket 'l and IL., andf may be drivenfromxshaft 5 at the bottom. .Asiv the construction 'and-operation of thetwo sides are' alike, .only one side will be described in detail. V vYEach chain, [3. travelsbetween' two guideflanges 4l5 and |16. vvhichmay be madeof angle irons' suitably secured` tothe sideV 5 of the.housingv and the yside 6 carries 'similar "guide *flanges (not shown)Chain I3.v has notches lgfi'n its, outer periphery in linksfl'ocatedatzsuitablyspaced ntervals, `the notches being formed, in` the modlfication illustrated, in thev thin 'or innerflinksjof the chain.vrTransverse supportrod's Zfoarrying sleeves. or bearings V21 at' theiren ds are; received in corresponding notches- |79 `of,-Ieach. chain; and

carry panels, 422,. ory sheets, of` asuitable 'ltjer ima-Vjsheet-offmetal mesh.. fabrics folded double' vr a 50.`

panel to cross over without interference.

f described.

clip 23. However, any other suitable filter Amaterial may be employed,which may be mounted on any suitable swivel or pivot carried in notchesI9. As shown, the panels 22 are substantially double the distancebetween notches in the chainv so that on the straight nights the panelsare imbricated to form a substantially continuous filter curtain on theexterior of the chain on the upstream side, with one face, hereinafterdesignated as the upstream face, presented to the air stream.

Thejinve'ntion, vwhich is directed to an arrangement for reversing theindividual filter panels at one end of their travel so as to cause themto present the same face upstream on the return flight of their travel,now will be de-k scribed. The exterior track or guide channel l isexpanded at the top end at 26to embrace the periphery of transfersprocket l2, and the track may be similarly expanded at 21 at the bottomto embrace the bottom transfer sprocket 8. The inner track deflectsinwardly at 28 to guide the cha-in inwardly to the chain sprocket H andwhen a notched link registers with a notch in the transfer sprocket l2the rod 20 in the link is picked up by the pair of transfer sprockets l2and carried around thereby to the point where the chain again registerswith the transfer sprocket, at which point the rod reenters a chainnotch. 'I'he absence of a cross shaft between sprockets l2 at the topallows the filter A leaf spring 29 is provided at the top to engage thepanels as they come around on the discharge side of the transfersprocket to compel their overlap on the interior, so that when the rods20 are picked up by the chain at the beginning of the downward flightthe panels are arranged .with each panel overlapping the adjacent lowerpanel on the inside of the chain, and all panels present their upstreamfaces upstream, as they move downwardly toward the oil bath. Thus, eachpanel is braced by the rod of the next lower panel so the panels cannotseparate to allow air to blow through. The downstream opening 3 issealed with respect to the filter curtain by sealing strips in knownmanner to prevent air bypassing the curtain.

At the bottom, the swivel rods 20 are picked up from the chain by thetransfer sprockets 8 and are carried around the expanded guide track 21through the washing bath where they are washed and, upon rising on thedischarge side, are again taken up by the chain in overlapping positionon the exterior of the chain with the same face upstream. This avoidsdipping the chain into the washing iiuid and gives each panel anopportunity to drain before it is picked up by the chain.

The operation of the invention now will be The chains i3 are driven fromshaft 5 and may be advanced intermittently as required or at a slowcontinuous rate. As each rod 20 carrying a filter panel 22 reaches thebottom transfer sprockets 8, it is removed from the chain'and is loweredin the track formed by sprocket 8 and ange 21 into the washing bath intrough 4. Accumulated dust is washed off the panel and the panelreceives a fresh coat of liquid. The panel is given an opportunity to'drain and is then picked up by the chain and carried into the opening 2in overlapped relation to the next following panel. At the top, as eachrod reaches the transfer sprockets, it is picked up out of the chainnotch and is carried around 26 while it dangles from the sprockets. Atthe opposite side the leaf spring 29 deflects the panel inwardly tocause it to overlap the preceding panel on the inside, and on thedownward course the same face of each panel is presented upstream as onthe upward course. This eliminates the danger of the stream of airdisloding dust from the downstream panel.

If desired, the filter curtan may be driven at the top from a shaftcarrying gears or sprockets meshing with the transfer sprockets I2 andof such' diameter that the filter `panels will clear the shaft in theirtransfer. Various other modifications may be made in the inventionwithout departing from the spirit or scope thereof.

I claim as my invention: 1

1. In an air stream iilter of the imbricated panel type: pairs of spacedconveyor sprockets; a pair of endless chains having slotted linkspassing around said conveyor sprockets providing advacing and returncourses across an air stream; rods carried in said slotted links, each.rod carrying a filter panel, the length of the filter panels and thespacing of the rods providing an imbricated panel curtain; and pairs ofrotatable transfer sprockets of larger diameter than the chain sprocketslocated at the ends of the courses to engage and remove said rodssuccessively from one course and transfer the rods to the other coursein inversed imbricated panel relation.

2. In a filter of the overlapped panel type: an endless conveyorproviding advancingv and return air-cleaning passes across an airl llowpassage and a crossover course from the end of each pass to thebeginning of the other pass; a succession of lapping panels along eachpass, each panel extending transversely across the conveyor, each beingremovably mounted on the conveyor along each pass and each presentingthe same face upstream on each pass but being arranged on one pass tooverlap the front side and one transverse edge of the following paneland being inversely arranged on the other pass to underlap the back sideand the opposite transverse edge of the following panel so as to form animbricated curtain on each pass with the adjacent panels of one curtainin one relationship and of the other curtain in relatively inversedrelationship; and transfer means located adjacent one crossover courseto remove successive panels from the conveyor at the end of one pass,move each panel outwardly from the conveyor and around the adjacentcrossover course to clear the panel from and inverse its relation- Shipto the following panel and then feed the inversed panel back to theconveyor at the beginning of the other pass, said. transfer meansincluding a panel-engaging member mounted for movement in timedrelationship to the conveyor over a predetermined path which loopsoutwardly around the adjacent crossover course from one side of theconveyor to the other.

3. In the lilter of claim 2 wherein: at least a portion of that sectionof the conveyor, providing said one crossover course, extends about anaxis in a circular path; and said member moves about the same axis overa larger circular path.

4. In the iilter of claim 2 wherein: at least a portion of that sectionof the conveyor, providing said one crossover course, passes aroundconveyor sprockets; and said member is in the form of a larger sprocketmounted for rotationwith the conveyor sprocket about the .same axis.

veyor extends around conveyor sprockets at each ,3

crossover course; and said member for each transfer means is in the formof a larger sprocket mounted for movement with the adjacent conveyorsprocket and about the same axis.

VERNER DAHLMAN.

6 REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,836,131 Richter Dec. 15, 19312,070,872 Strindberg Feb. 16, 1937 o FOREIGN PATENTS Number Country Date365,723 Great Britain Jan. 28, 1932 576,709 Germany May 18. 1933

